If you're a typical car crafter, one of the first performance-engine parts you bought was probably a dual plane intake manifold. A well-designed dual plane intake can improve torque, add horsepower, and make that otherwise stock engine look a little more aggressive. But it wasn't until we started counting did we realize the incredible variety of choices when it comes to choosing a dual plane intake manifold for a small block Chevy. We collected a 23-deep pile of dual plane intakes to continue with our small block Chevy dual plane intake comparison. The collection of manifolds could have been even larger, but we limited our test to the'55–'86-style bolt pattern. We bypassed both the Vortec intake and the '87 to mid-'90s intakes, on which the four center-bolt angles were altered. We mentioned that this intake comparison is part of a series of small block Chevy components testing we've completed. The first was a budget cylinder head-test in the Sept. '12 issue ("Eight-Budget-SBC-Head Shootout"), in which we wrestled eight less-than-$1,000 heads on our Slayer 350 small block Chevy. The following month, we looked at a bunch of inexpensive four-barrel carburetors ("The Great $299 Carburetor Shootout," Oct. '12). Most recently, in our June '13 issue, we completed our massive single-plane comparison ("The Great Intake Flog"), testing 19 intakes on our 406ci small block that is this month's test mule. A little teaser: If you were to combine the "winners" of these previous tests, you would have a fairly powerful combination—and that's exactly what you can expect us to do in an upcoming issue. That's our not-so-subtle way to keep you reading Car Craft.

Dual Plane Intake Test Engine

As we did with our single plane intake comparison, we are using the 406ci small block Chevy first introduced in the May '11 issue ("Build a 400ci Torque Monster For $2,500") and later rebuilt as "Build Big-Hammer Power" in the Dec. '11 issue. We've decided to call this engine Rodney Dangerfield because it gets no respect— only abuse. By the time we were done with this test, the 406 had slogged through more than 150 dyno runs with nary a whimper. The engine is basically the same as the one used in the June '13 single plane intake test, with a change to a milder Crane camshaft that is more in line with what would be used in a dual plane intake application. We've retained the same Crane Gold 1.6:1 roller rockers and 0.080-inch-wall pushrods. We also retained the TFS 215cc heads used in the previous test to ensure we could flow enough air to evaluate the intake manifolds and not the cylinder heads. Because we didn't expect to exceed 500 hp, we chose a more compatible 750-cfm Holley HP mechanical-secondary carburetor that worked well out of the box, needing only minor jet and air-bleed changes from time to time to ensure the air/fuel (A/F) ratio curve remained between 12.5 and 13.1:1. Finally, Westech's 13⁄4-inch dyno headers and 3-inch Flowmaster mufflers directed the exhaust.

Dual Plane Intake Test Procedure

With this many intake manifolds, we expected the competition would be very close. This demanded a very accurate test procedure to achieve best results. This meant that Westech dyno guru Steve Brulé had to control several variables, the most important of which was A/F ratio. Because we were using a carburetor, the A/F ratio is subject to significant swings based on manifold design. Carburetors also don't produce the same A/F ratio throughout the entire power curve. We made sure each test maintained an A/F ratio range within 12.5:1 and 13.1:1. That was the best we could do without custom-tuning the carburetor for each manifold. We also made sure the oil temperature was consistent for each test because cold oil can cost upwards of 5–10-lb-ft of torque and similar horsepower numbers. These requirements eventually dictated a test procedure in which we would subject each manifold to anywhere from three to five test runs until we had two curves within 0.5 percent. Then we averaged those two runs into a single curve. This eliminates an individual "hero" run from tweaking our results. In order to maintain timing accuracy, we used an MSD crank trigger with total timing set to 34 degrees, removing the variable of resetting the timing each time we changed manifolds. We also re-ran the first intake manifold tested at the end of the test to ensure that our 406 was still producing the same power. When the re-test gave us nearly identical results from the first run three days earlier, we knew our tests were as accurate as we could produce.

Overall, the dual plane intake test required the better part of three days, but we think accurate results were well worth the effort. Also, the TFS aluminum 215cc heads now have had nearly 50 intakes bolted to them, and those intake threads in the heads have held up just fine. Hero status is awarded to whomever does the heat-treating on those TFS heads! A big thank you to Fel-Pro for all the intake gaskets we blew through in this test and to Permatex for the big tubes of The Right Stuff RTV we used to keep the oil inside the engine. We've also used the Ultra Grey and Ultra Black with great results. Finally, thanks to Summit Racing for supplying a large pile of 3⁄8- and 1⁄2-inch Allen pipe plugs to seal up many of these manifolds. The Holley intakes came with plugs, though most of the other intakes do not.

Short Manifolds (Less Than 5.00 Inch Carb Pad Height)

Manifold

PN

Price

Peak TQ

Peak HP

Avg. TQ

Carb Ht.

TQ at 3,000

Edelbrock EPS

2701

$139.95

506

461

466.2

4.80

476

Edelbrock Air Gap

2601

$225.95

504

458

464.7

4.92

478

Chevrolet ZZ4

10185063

$239.95

500

471

464.5

4.95

467

Weiand Street Warrior

8125

$151.95

501

463

463.5

3.65

470

Weiand Street Warrior

8120

$134.95

502

459

462.8

4.62

471

Summit Stage 1

226012

$131.95

498

459

461.0

4.65

468

Edelbrock Performer

2101

$157.95

494

456

459.1

4.60

470

Prof. Prod.
Cyclone

52001

$143.95

487

436

449.3

4.72

471

5/16Our test engine is the same 406ci small-block we used for the single-plane intake manifold test, with a change to more conservative cam timing that is closer to what would be typical for a dual-plane intake manifold–equipped engine. We also used a smaller 750hp Holley carburetor instead of the 850 Ultra HP employed in the single-plane test.

6/16Edelbrock says the EPS is worth 9 lb-ft over the 2101 on a 350ci engine. We saw 12 lb-ft with our 406 over the 2101, and the EPS bettered the 2601 Performer Air Gap in average torque. Even better, the EPS saves $20 over the 2101. Within the short manifolds, the EPS is an excellent choice.

Medium Manifolds (5.00 to 5.30 Inches Carb Pad Height)

Manifold

PN

Price

Peak TQ

Peak HP

Avg. TQ

Carb Ht.

TQ at 3,000

AFR Titon

4804

$579.00

510

484

473.6

5.29

467

Edelbrock Air Gap

7501

$234.95

508

474

471.2

5.26

473

Edelbrock RPM

7101

$174.95

504

470

468.3

5.25

474

Weiand Warrior

8501

$217.95

504

466

466.3

5.24

471

Summit Stage 3

226010

$182.95

503

464

465.6

5.25

471

Edelbrock RPM Q-Jet

7104

$199.95

501

465

465.3

5.25

471

Summit Stage 2

226014

$132.95

502

469

464.9

5.18

466

Weiand Speed War

8150

$145.95

502

467

464.9

5.18

467

Jegs

513000

$ 99.99

500

471

464.5

5.29

462

Professional Products Crosswind

52026

$199.95

496

457

459.5

5.24

469

Tall Manifolds (5.30 Inches and Taller)

Manifold

PN

Price

Peak TQ

Peak HP

Avg. TQ

Carb Ht.

TQ at 3,000

Professional Products Typhoon

52021

$162.95

499

469

465.3

5.33

471

TFS StreetBurner

30400222

$224.95

501

465

465.2

5.39

473

Dart SHP

42811000

$231.70

501

464

463.7

5.52

470

Professional Products Cyclone-Plus

52013

$177.95

497

458

461.0

5.37

471

Chevy Iron

14096011

$261.06

494

457

459.0

5.45

468

Peak Torque and Horsepower

We have to acknowledge how amazingly tight this field is in terms of peak torque. How close? It is fair to say that it would be difficult to feel the difference of 2 percent of power. That's 10 lb-ft of torque, the difference between the Third Place Edelbrock EPS manifold at 506 lb-ft and the Professional Products Crosswind (52026), which placed 20th. Also note that in the peak-torque category, three of the top five manifolds are Edelbrock castings. When it comes to dual-plane intakes, torque is king, and it appears the Edelbrock has this part of the power curve dialed in.

Torque at 3,000 rpm is another important category that we listed in the initial description chart for each manifold. We opted to include this bit of data because it relates to low-speed power. With a performance torque converter, this would be just after the converter hits. Note that the relatively short Edelbrock 2601 Performer Air Gap manifold makes more torque at 3,000 than any other manifold. Compare its 478 lb-ft to the Jegs manifold's 462 lb-ft, to see that the Air Gap makes 16 lb-ft more torque. We guarantee you will feel 16 lb-ft in the seat of your pants. We think this can be partially attributed to the plenum-wall cutout on the Jegs manifold, but the TFS and Dart manifolds also have this feature, and those manifolds are only down by a single-digit compared with the Edelbrock. For a mild street engine (especially with stock or near-stock heads), this low-speed torque value should be given greater consideration.

Now let's talk peak horsepower. While the field gets a little more spread out in this category, the difference between the Third-Place Jegs Champion and the 21st place Edelbrock Performer is only 15 hp—barely a 3 percent increase. By now, it should be obvious that any manifold you choose within the top 20 will work just fine for a street small-block. Keep in mind that this test used really good heads on a large engine. With a mild 350 with near-stock heads, the differences in these manifolds would be much narrower. And we haven't even mentioned price yet.

10/16If peak torque and peak horsepower are your only goals, then look no further than the AFR composite manifold. Yes, it’s expensive, but it simply bested every other manifold.

Peak Torque and Horsepower

Ranking

Peak TQ

Ranking

Peak HP

1st

AFR Titon

510

1st

AFR Titon

484

2nd

Edelbrock 7501

508

2nd

Edelbrock 7501

474

3rd

Edelbrock EPS 2701

506

3rd

Jegs Champion

471

4th

Edelbrock RPM 7101

504

4th

Edelbrock RPM 7101

470

4th

Weiand Warrior 8501

504

5th

Pro. Prod 52021

469

4th

Edelbrock 2601

504

5th

Summit 226014

469

7th

Summit 226010

503

7th

Weiand 8150

467

8th

Summit 226014

502

8th

Weiand 8501

466

8th

Weiand Warrior 8150

502

9th

Edelbrock 7104

465

8th

Weiand 8120

502

9th

TFS Street Burner

465

11th

TFS StreetBurner

501

11th

Summit 226010

464

11th

Edelbrock 7104

501

11th

Dart SHP

464

11th

Dart SHP

501

13th

Weiand 8125

463

11th

Weiand 8125

501

14th

Edelbrock 2701

461

15th

Chevy ZZ4

500

15th

Weiand 8120

459

15th

Jegs Champion

500

15th

Summit 226012

459

17th

Pro. Prod. Typhoon

499

17th

Edelbrock 2601

458

18th

Summit 226012

498

17th

Pro. Prod. 52013

458

19th

Prof. Prod. 52013

497

19th

Pro. Prod. 52026

457

20th

Prof. Prod. 52026

496

19th

Chevy Iron

457

21st

Edelbrock 2101

494

21st

Edelbrock 2101

456

21st

Chevy Iron

494

22nd

Chevy ZZ4

451

23rd

Pro. Prod. Cyclone

487

23rd

Pro. Prod. 52001

436

Average Torque and Average Torque per Dollar

Here's where we lay it on the line. For street engines, it's not peak horsepower that makes your engine feel powerful. Street-smart engine builders emphasize torque, and while peak torque is a good indicator, we think the best judge of a dual-plane intake is average torque. This generates a single number created by averaging all the torque numbers within the test range of 2,500 and 6,200 rpm. We weren't surprised when the AFR Titon composite manifold handily won this contest. What was surprising was the tried-and-true Edelbrock Performer RPM Air Gap was within 2.4 lb-ft of the AFR at less than half the cost. It's also important to note that this evaluation really splits hairs because nearly all these manifolds produce excellent power. Let's take the Weiand 8125 Street Warrior. It made 500 lb-ft of peak torque yet is listed 15th in average torque. But when we plugged its torque curve into our Quarter, Pro dragstrip simulation, this intake is only off 0.15-second and 1 mph compared with the fourth-rated Edelbrock 7101. So you can see that most of these manifolds really do a decent job. Drop out the top and bottom two manifolds, and the total spread between 3rd and 20th is 2 percent—or 9.2 lb-ft of average torque.

For the typical car crafter, average torque per dollar is probably most important of all the ratings in this shootout. Unless your name is Bill Gates, cost and power are equally important. To come up with this evaluation, we divided the manifold's average torque by its price; the larger the number, the more power it delivers for each dollar spent. From the moment we began pricing manifolds, the Jegs Champion appeared to be a front-runner. At $99.99, all this intake had to do was make decent torque and horsepower to win this category. But, as you've seen, this intake ranked Third in peak horsepower and was capable of 500 lb-ft of torque. Trim $30 off its next closest price rivals, and the conclusion is simple: If we were to mash up all the evaluations into one overall winner, you could make a great case for the Jegs Champion intake. Note that the AFR number is a fraction, which means its price was a larger number than its average torque.

11/16The Weiand Speed Warrior 8501 also separates the runners from the manifold floor. It placed a respectable Fourth in average torque and sixth in average torque per dollar, making it an excellent choice.

Average Torque and Average Torque per Dollar

Ranking

Avg. TQ

Ranking

Avg. TQ/$

1st

AFR Titon

473.6

1st

Jegs Champion

4.64

2nd

Edelbrock 7501

471.2

2nd

Summit 226014

3.49

3rd

Edelbrock 7101

468.3

3rd

Summit 226012

3.49

4th

Weiand 8501

466.3

4th

Weiand 8120

3.43

5th

Edelbrock 2701

466.2

5th

Edelbrock 2701

3.31

6th

Summit 226010

465.6

6th

Weiand 8150

3.18

7th

Edelbrock 7104

465.3

7th

Pro. Prod. 52001

3.12

7th

Pro. Prod. 52021

465.3

8th

Weiand 8125

3.05

9th

TFS StreetBurner

465.2

9th

Edelbrock 2101

2.90

10th

Summit 226014

464.9

10th

Pro. Prod. 52021

2.85

10th

Weiand 8150

464.9

11th

Edelbrock 7101

2.67

12th

Edelbrock 2601

464.7

12th

Pro Prod. 52013

2.59

13th

Jegs Champion

464.5

13th

Summit 226010

2.54

14th

Dart SHP

463.7

14th

Edelbrock 7104

2.32

15th

Weiand 8125

463.5

15th

Pro. Prod. 52026

2.29

16th

Weiand 8120

462.8

16th

Weiand 8501

2.14

17th

Summit 226012

461.0

17th

TFS StreetBurner

2.06

17th

Pro. Prod. 52013

461.0

18th

Edelbrock 2601

2.05

19th

Pro. Prod. 52026

459.5

19th

Edelbrock 7501

2.00

20th

Edelbrock 2101

459.1

20th

Dart SHP

2.00

21st

Chevy Iron

459.0

21st

Chevy ZZ4

1.89

22nd

Chevy ZZ4

454.4

22nd

Chevy Iron

1.76

23rd

Pro. Prod. 52001

449.3

23rd

AFR Titon

0.82

In-Car Power

What will all this power do in a car? We simulated the 7101 Edelbrock Performer RPM's power curve in a 3,450-pound Chevelle with 3.55:1 gears, a 2004R automatic, 3,000-rpm stall-speed converter, 26-inch-tall Mickey Thompson ET Street tires, and shifting at 6,400 rpm. The Quarter, Pro simulation reported that the Chevelle could run 11.50s at 117 mph with a 1.55-second 60-foot time. That's impressive for a 470hp dual-plane–equipped small-block. Keep in mind that strong average torque is what makes this combination so quick. If you recall, our single-plane intake test—with the same 406ci engine with a bigger cam—the motor made as much as 559 hp, but in the same simulated car with the same equipment, the greater horsepower only pushed the Chevelle to 11.30s at 120 mph. With more gear (like a 4.10:1, for example), the car would probably run 11-teens in the higher-horsepower configuration.

15/16Through it all, our Rodney 406 braved more than 150 dyno pulls, and we’re not finished yet. It might just find its way into our Orange Peel Chevelle.

Cam Specs

Crane Roller: PN 118571

Duration at 0.050 (Degrees)

Valve Lift W/ 1.5:1 (w/ 1.6:1 rockers)

Lobe-Separation Angle (degrees)

Intake

232

0.525 (0.560)*

112

Exhaust

240

0.543 (0.579)*

*This is gross lift. We set the lash at 0.020 inch, which must be subtracted from the gross-lift number to produce a net lift equaling 0.540/0.559.

16/16As with our single-plane test, taller manifolds generally make more power—although not always, as the results will show. The Performer RPM Air Gap separates the intake runners from the hot oil bouncing off the bottom of the manifold to reduce inlet-air temperatures. When choosing a manifold, keep in mind that it has to fit under the hood.

Test Parts List

Description

PN

Source

Price

TFS 215cc heads

32400007

Summit Racing

$1,449.95

Crane roller cam

118571

Summit Racing

426.00

Crane roller lifters

11552-16

Summit Racing

428.80

Crane roller rockers

11755-16

Summit Racing

395.20

Crane pushrods

95642-16

Summit Racing

156.80

Crane thrust button

99164-1

Summit Racing

14.00

Fel-Pro head gasket

1143

Summit Racing

88.95 (2)

Fel-Pro int. gasket

1206

Summit Racing

16.95

MSD crank trigger

8615

Summit Racing

255.95

MSD distributor

85551

Summit Racing

235.95

MSD plug wires

31229

Summit Racing

84.95

Autolite spark plugs

AR3933 (8)

Summit Racing

28.00

ARP head bolts

134-3701

Summit Racing

84.28

ARP intake bolts

434-2001

Summit Racing

33.70

Permatex Ultra Gr.

82194

Local Auto Parts

7.49

Carb adapter plate

2732

Summit Racing

6.95

3⁄8-inch pipe plugs (4)

G1482

Summit Racing

5.95

1⁄2-inch pipe plugs (4)

G1483

Summit Racing

5.95

And the Winner Is…

We will leave the final selection entirely up to you. If your budget screams for help, the Jegs Champion intake is the wallet-friendly choice. If power is your only goal, the AFR Titon is clearly the best, hands down. If power and price demand equal attention, either the Edelbrock Performer EPS (2701) Air Gap or the 8150 Weiand Speed Warrior or the Summit Stage 2 will certainly deliver. Frankly, any of the manifolds ranked in the top 15 of all our evaluations are solid choices that won't leave you with buyer's remorse. We hope we've removed some of the guesswork from your next manifold purchase.